The objective of this research program is to determine the effects of perinatal exposure to testosterone or 17 beta estradiol on subsequent tissue responses. Mammary and endocrine morphology and sytemic hormone balance will be assessed after exposure to chemical carcinogen. The relation between carcinogen-induced changes in morphology of the mammary gland and endocrine organs and the circulating levels of estrogen, progesterone, growTh hormone and prolactin will be described. Mammary morphologic responses to various hormone combinations will be compared in vitro between control tissues and tissues from perinatally hormone- treated animals. Permanent cellular alterations in mammary tissues will be identified by alterations in differentiative response to hormones in organ culture.